http://bugs.ntp.org/show_bug.cgi?id=2646
https://bugs.gentoo.org/533966

--- a/ntpd/ntpd.c
+++ a/ntpd/ntpd.c
@@ -971,8 +971,8 @@ getgroup:
 			char *captext;
 			
 			captext = (0 != interface_interval)
-				      ? "cap_sys_time,cap_net_bind_service=pe"
-				      : "cap_sys_time=pe";
+				      ? "cap_ipc_lock,cap_sys_time,cap_net_bind_service=pe"
+				      : "cap_ipc_lock,cap_sys_time=pe";
 			caps = cap_from_text(captext);
 			if (!caps) {
 				msyslog(LOG_ERR,
